Modern composite materials are applied extensively in manufacturing. The manufacturing methods of composite materials include spray-up, resin transfer molding (RTM), and filament winding, wherein spray-up and RTM rely on handiwork, and thereby the repeatability of product characteristics is poor.
Filament winding is winding molds with fibers impregnated with resin for manufacturing hollow tubes or containers. The applications thereof include diving oxygen cylinders and fuel storage containers for automobiles. Because composite materials have superior characteristics to metal materials in specific strength, anti-corrosion capability, formability, and cost, for most containers accommodating liquid or gas, better durability is attained. Thereby, in the present day, the method for manufacturing most containers is filament winding of composite materials. The method uses fibers impregnated with resin to wind a container mold core for forming a container. The composite materials used for winding the container are fibers impregnated in advance with resin before winding is performed. Alternatively, fibers first pass through a resin trough for impregnating with resin right before winding is performed.
Presently, products usually manufactured using filament winding are pressure containers, such as oxygen cylinders and fuel containers. The filament winding according to the prior art uses fibers to wind one side of a mold core for forming a tube or a container with identical opening sizes on both ends. Thereby, it can be applied to a filament-winding machine with automatic controls for mass-producing tubes or containers. Current filament winding has better production efficiency, simpler processes, and less sophisticated specifications. However, it is because of the simple processes and standardization, current filament winding cannot control precisely the winding angles of fibers. Consequently, current filament winding can only calculate and control a single winding angle of fibers on mold cores for fabricating composite containers with identical opening sizes on both ends but cannot fabricate composite containers with distinct opening sizes on both ends. In order to fabricate composite containers with distinct opening sizes on both ends, other manufacturing methods, such as spray-up and RTM, have to be applied. Nevertheless, the costs of said manufacturing methods are higher than the cost of filament winding. In addition, the production efficiencies of said manufacturing methods are lower than that of filament winding.
Therefore, how to find a method which can not only solve the limitation of composite materials in manufacturing unequal openings containers but also upgrade the mass production capabilities has been our long term goal. The novel manufacturing method according to the present invention can fabricate filament wound containers with arbitrary unequal openings.